scholarly journals Depletion of CD45RA+ Cells from Mobilized Peripheral Blood Stem Cell (PBSC) Collections As an Integral Part of Hematopoietic Stem Cell Transplantation (HSCT) and Cellular Therapy (CT)

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1130-1130
Author(s):  
Ping Law ◽  
Paul W. Eldridge ◽  
James Houston ◽  
Brandon M. Triplett ◽  
David R Shook ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
Conflicts Of Interest ◽  
Cell Depletion ◽  
Clinical Scale ◽  
Hematopoietic Stem ◽  
Naive T Cells ◽  
Naïve T Cells ◽  
Cd34 Cells ◽  
Before And After

Abstract Clinical scale depletion of CD45RA+ naïve T cells from leukapheresis collections can be achieved using CliniMACS (Bone Marrow Transplant. 2013, 1-7). In this study, PBSC collections depleted of CD45RA+ cells were infused as part of CT treatment protocols for pediatric patients with hematologic malignancies and solid tumors in 2 separate clinical trials. Between Sep 2012 and May 2014, a total of 25 CD45RA+ cell depletion procedures was performed for 25 patients. Mobilized PBSC leukapheresis units were collected (using Spectra) from HLA haplo-identical donors and held overnight in cold prior to cell selection. Characterization of the products before and after CD45RA+ cell depletion is shown in Table 1. Depletion of all CD45RA+ cell averaged to 3.39-log while depletion of CD3+CD45RA+ T cells was > 3.76-log, as this subset of cells became undetectable in 8 (out of 25) final products. CD34+ cell recovery was 65.4%, similar to that of CD3+CD45RO+ T cells (65.1%), which constituted > 99% of all T cells after depletion. From the PBSC collection, each patient received a median dose of 0.009 x 106 CD3+CD45RA+ cells/kg and 11.1 x 106 CD34+ cells/kg. The final product contained a substantial amount of CD14+ monocytes (median = 22.0%, range: 7.0 – 46.4), few CD56+ NK cells (3.1%, range: 1.3 – 8.1) and almost no CD19+ B cells (0.04%, range: 0.01 – 0.30). After processing the cells were resuspended in Plasmalyte + 5% human serum albumin and infused as soon as possible. There was no reported contamination (growth of bacteria – aerobic or anaerobic and fungus) in the final cell products and no infusion related adverse events were observed. In conclusion, we have demonstrated clinical scale depletion of naïve T cells can be achieved consistently and the final cell product can be safely infused into patients as part of HSCT and / or CT program. Table 1: Cell Populations (Median & ranges) Before and After CD45+ Cell Depletion Before Depletion After Depletion Total Nucleated Cells 3.97 x 1010 (1.55 – 6.60) 1.47 x 1010 (0.43 – 2.92) % CD34+ Cells 0.85% (0.29 – 2.30) 1.45% (0.32 – 4.63) % CD3+ T Cells 22.8% (11.5 – 50.9) 13.1% (3.9 – 37.7) % CD45RA+ Cells 39.6% (27.2 – 64.1) 0.05% (0.01 – 0.79) % CD3+ CD45RA+ Naïve T Cells 12.3% (4.3 – 29.2) 0.01% (0 – 3.42) % CD3+ CD45RO+ Memory T Cells 6.5% (2.0 – 15.6) 13.0% (3.9 – 37.5) Disclosures No relevant conflicts of interest to declare.

Robust Production of Cytomegalovirus pp65-Specific T Cells By a Fully Automated IFN-γ Cytokine Capture System

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 5739-5739
Author(s):  
Nayoun Kim ◽  
Young-Sun Nam ◽  
Keon-Il Im ◽  
Jung-Yeon Lim ◽  
Young-Woo Jeon ◽  
...  
Keyword(s):  
T Cells ◽  
Conflicts Of Interest ◽  
Target Cells ◽  
Cytotoxic Lymphocytes ◽  
Isolated Cells ◽  
Hematopoietic Stem ◽  
Naive T Cells ◽  
Naïve T Cells ◽  
Magnetic Enrichment ◽  
Ifn Γ

Abstract Cytomegalovirus (CMV) related diseases are a serious cause of morbidity and mortality following hematopoietic stem cell transplantation (HSCT). As an alternative to antiviral drugs, CMV-specific cytotoxic lymphocytes (CMV-CTLs) can provide long-term CMV-specific immunity without major side effects. In this study, we apply the IFN-γ cytokine capture system (CCS) using the fully automated CliniMACS Prodigy device to rapidly produce CMV-CTLs. Five validation runs were performed using apheresis samples from randomly selected CMV-seropositive healthy blood donors. CliniMACS Prodigy automatically performed successive processes including antigen stimulation, anti-IFN-γ labelling, magnetic enrichment, and elution which took approximately 13 hours. The original apheresis samples consisted of 0.3% CD3+IFN-γ+ T cells which were mainly CD45RA+CD62L+ naïve T cells. Following IFN-γ enrichment, the target fraction contained 51.3% CD3+IFN-γ+ cells with reduction in naïve T cells and the selection of CD45RA-CD62L- and CD45RA+CD62L- memory T cells. Interestingly, the frequency of CMV pp65 specific CD3+ T cells was also increased by 1.7-fold. Furthermore, extended culture of isolated cells revealed efficient proliferation with sustained antigen-specific IFN-γ secretion and cytotoxicity against pp65 pulsed target cells. Therefore, we suggest IFN-γ CCS by CliniMACS Prodigy as a simple and robust approach to produce CMV-CTLs, which may be highly feasible and applicable for clinical use. Disclosures No relevant conflicts of interest to declare.

Factors affecting thymic function after allogeneic hematopoietic stem cell transplantation

Blood ◽  
2001 ◽  
Vol 97 (5) ◽  
pp. 1458-1466 ◽  
Author(s):  
Kenneth Weinberg ◽  
Bruce R. Blazar ◽  
John E. Wagner ◽  
Edward Agura ◽  
Brenna J. Hill ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Hematopoietic Stem Cell Transplantation ◽  
Stem Cell Transplantation ◽  
Hematopoietic Stem ◽  
Thymic Function ◽  
Naive T Cells ◽  
Naïve T Cells ◽  
History Of

Hematopoietic stem cell transplantation (HSCT) is followed by profound immunodeficiency. Thymic function is necessary for de novo generation of T cells after HSCT. Circulating CD45RA+ naive T-cell levels are predictive of antigen-specific T-cell responses in the absence of graft-versus-host disease (GVHD). These T cells may not represent recent thymic emigrants, since naive T cells may maintain this phenotype if not antigen-activated. To accurately measure thymic output after HSCT and determine the factors that influence thymic function, T-cell receptor excision circles (TRECs) were examined in CD4+ and CD8+ cells from a cross-section of patients following HSCT. TREC levels rose weeks after HSCT and could be detected in patients 6 years after HSCT. TREC levels correlated with the frequency of phenotypically naive T cells, indicating that such cells were not expanded progeny of naive T cells present in the donor graft. Chronic GVHD was the most important factor that predicted low TREC levels even years after HSCT. Patients with a history of resolved GVHD had decreased numbers of TREC, compared with those with no GVHD. Because few adults had no history of GVHD, it was not possible to determine whether age alone inversely correlated with TREC levels. Recipients of cord blood grafts had no evidence of decreased TREC induced by immunosuppressive prophylaxis drugs. Compared with unrelated donor grafts, recipients of matched sibling grafts had higher TREC levels. Collectively, these data suggest that thymopoiesis is inhibited by GVHD. Larger studies will be needed to determine the independent contributions of age and preparative regimen to post-transplant thymopoietic capacity.

Generation of Human T/NK Cell Precursors for Adoptive Transfer To Enhance Immune Reconstitution in Allogeneic Hematopoietic Stem Cell Transplantation Recipients.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3209-3209
Author(s):  
Sonali Chaudhury ◽  
Johannes Zakarzewski ◽  
Jae-Hung Shieh ◽  
Marcel van der Brink ◽  
Malcolm A.S. Moore
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Hematopoietic Stem Cell Transplantation ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Hematopoietic Stem ◽  
Serum Free ◽  
Cd34 Cells

Abstract Allogeneic hematopoietic stem cell transplantation (HSCT) is associated with significant post-transplant immunoincompetence which affects in particular the T cell lineage and results in an increased susceptibility to infections. Novel strategies to enhance immune recovery after HSCT could prevent malignant relapse and immune deficiency and improve the overall outcome of this therapy. We have established a serum free culture system using murine bone marrow stroma expressing the Notch ligand Delta-like 1 (DL1) to obtain high numbers of human pre-T cells from CD34+ cells. Human cord blood CD34+ cells were plated on OP9 DL1 stroma transduced with adenovirus expressing thrombopoietin (ad-TPO) at an MOI of 30. Media used was QBSF-60 (Serum free media prepared by Quantity Biologicals) supplemented with Flt-3 ligand and IL-7 (10ng/ml). At 4–5 weeks we obtained a 10 5–10 7 fold expansions of cultured cells of which about 70–80% were CD5, CD7 positive pre T cells (Fig 1). We then developed an optimal system to study human lymphohematopoiesis using mouse models (NOD/SCID/IL2rϒnull and NOD/SCIDβ2null) and established an adequate pre T cell number (4 × 10 6) and radiation dose (300 Rads). We injected CD34 and pre-T cells (CD45 +, CD4−, CD5+, CD7+) derived from OP9 DL1 cultures into these mice and achieved ~50%engraftment of NK in the bone marrow and spleen of the mice at 2 weeks following transplant. The thymus from the same mice showed evidence of about 12–15% CD7+ pre T cells. We are currently studying the function of the generated NK and T cells both in vivo and in vitro studies. Figure Figure

A Modified HIV1-Based Lentiviral Vector Can Transduce Rhesus Hematopoietic Repopulating Cells as Efficiently as An SIV Vector in An Autologous Transplantation Model.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 692-692
Author(s):  
Naoya Uchida ◽  
Phillip W Hargrove ◽  
Kareem Washington ◽  
Coen J. Lap ◽  
Matthew M. Hsieh ◽  
...  
Keyword(s):  
T Cells ◽  
Blood Cells ◽  
Conflicts Of Interest ◽  
Lentiviral Vector ◽  
Autologous Transplantation ◽  
Vector System ◽  
Transduction Efficiency ◽  
Large Animal ◽  
Hematopoietic Stem ◽  
Cd34 Cells

Abstract Abstract 692 HIV1-based vectors transduce rhesus hematopoietic stem cells poorly due to a species specific block by restriction factors, such as TRIM5αa which target HIV1 capsid proteins. The use of simian immunodeficiency virus (SIV)-based vectors can circumvent this restriction, yet use of this system precludes the ability to directly evaluate HIV1-based lentiviral vectors prior to their use in human clinical trials. To address this issue, we previously developed a chimeric HIV1 vector (χHIV vector) system wherein the HIV1-based lentiviral vector genome is packaged in the context of SIV capsid sequences. We found that this allowed χHIV vector particles to escape the intracellular defense mechanisms operative in rhesus hematopoietic cells as judged by the efficient transduction of both rhesus and human CD34+ cells. Following transplantation of rhesus animals with autologous cell transduced with the χHIV vector, high levels of marking were observed in peripheral blood cells (J Virol. 2009 Jul. in press). To evaluate whether χHIV vectors could transduce rhesus blood cells as efficiently as SIV vectors, we performed a competitive repopulation assay in two rhesus macaques for which half of the CD34+ cells were transduced with the standard SIV vector and the other half with the χHIV vector both at a MOI=50 and under identical transduction conditions. The transduction efficiency for rhesus CD34+ cells before transplantation with the χHIV vector showed lower transduction rates in vitro compared to those of the SIV vector (first rhesus: 41.9±0.83% vs. 71.2±0.46%, p<0.01, second rhesus: 65.0±0.51% vs. 77.0±0.18%, p<0.01, respectively). Following transplantation and reconstitution, however, the χHIV vector showed modestly higher gene marking levels in granulocytes (first rhesus: 12.4% vs. 6.1%, second rhesus: 36.1% vs. 27.2%) and equivalent marking levels in lymphocytes, red blood cells (RBC), and platelets, compared to the SIV vector at one month (Figure). Three to four months after transplantation in the first animal, in vivo marking levels plateaued, and the χHIV achieved 2-3 fold higher marking levels when compared to the SIV vector, in granulocytes (6.9% vs. 2.8%) and RBCs (3.3% vs. 0.9%), and equivalent marking levels in lymphocytes (7.1% vs. 5.1%) and platelets (2.8% vs. 2.5)(Figure). Using cell type specific surface marker analysis, the χHIV vector showed 2-7 fold higher marking levels in CD33+ cells (granulocytes: 5.4% vs. 2.7%), CD56+ cells (NK cells: 6.5% vs. 3.2%), CD71+ cells (reticulocyte: 4.5% vs. 0.6%), and RBC+ cells (3.6% vs. 0.9%), and equivalent marking levels in CD3+ cells (T cells: 4.4% vs. 3.3%), CD4+ cells (T cells: 3.9% vs. 4.6%), CD8+ cells (T cells: 4.2% vs. 3.9%), CD20+ cells (B cells: 7.6% vs. 4.8%), and CD41a+ cells (platelets: 3.5% vs. 2.2%) 4 months after transplantation. The second animal showed a similar pattern with higher overall levels (granulocytes: 32.8% vs. 19.1%, lymphocytes: 24.4% vs. 17.6%, RBCs 13.1% vs. 6.8%, and platelets: 14.8% vs. 16.9%) 2 months after transplantation. These data demonstrate that our χHIV vector can efficiently transduce rhesus long-term progenitors at levels comparable to SIV-based vectors. This χHIV vector system should allow preclinical testing of HIV1-based therapeutic vectors in the large animal model, especially for granulocytic or RBC diseases. Disclosures: No relevant conflicts of interest to declare.

The Tetraspanin CD9 Regulates Engraftment and Mobilization of Human CD34+ Hematopoietic Stem/Progenitor Cells and Modulates VLA-4 Activity

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1169-1169
Author(s):  
Kam Tong Leung ◽  
Karen Li ◽  
Yorky Tsin Sik Wong ◽  
Kathy Yuen Yee Chan ◽  
Xiao-Bing Zhang ◽  
...  
Keyword(s):  
Stem Cell ◽  
Progenitor Cells ◽  
Peripheral Blood ◽  
Scid Mouse ◽  
Conflicts Of Interest ◽  
Chimeric Mice ◽  
Hematopoietic Stem ◽  
Cell Engraftment ◽  
Cd34 Cells

Abstract Migration, homing and engraftment of hematopoietic stem/progenitor cells depend critically on the SDF-1/CXCR4 axis. We previously identified the tetraspanin CD9 as a downstream signal of this axis, and it regulates short-term homing of cord blood (CB) CD34+ cells (Leung et al, Blood, 2011). However, its roles in stem cell engraftment, mobilization and the underlying mechanisms have not been described. Here, we provided evidence that CD9 blockade profoundly reduced long-term bone marrow (BM; 70.9% inhibition; P = .0089) and splenic engraftment (87.8% inhibition; P = .0179) of CB CD34+ cells (n = 6) in the NOD/SCID mouse xenotransplantation model, without biasing specific lineage commitment. Interestingly, significant increase in the CD34+CD9+ subsets were observed in the BM (9.6-fold; P < .0001) and spleens (9.8-fold; P = .0014) of engrafted animals (n = 3-4), indicating that CD9 expression on CD34+ cells is up-regulated during engraftment in the SDF-1-rich hematopoietic niches. Analysis of paired BM and peripheral blood (PB) samples from healthy donors revealed higher CD9 expressions in BM-resident CD34+ cells (46.0% CD9+ cells in BM vs 26.5% in PB; n = 13, P = .0035). Consistently, CD34+ cells in granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood (MPB) expressed lower levels of CD9 (32.3% CD9+ cells; n = 25), when compared with those in BM (47.7% CD9+ cells; n = 16, P = .0030). In vitro exposure of MPB CD34+ cells to SDF-1 significantly enhanced CD9 expression (1.5-fold increase; n = 4, P = .0060). Treatment of NOD/SCID chimeric mice with G-CSF decreased the CD34+CD9+ subsets in the BM from 79.2% to 62.4% (n = 8, P = .0179). These data indicate that CD9 expression is down-regulated during egress or mobilization of CD34+ cells. To investigate the possible mechanisms, we performed a VCAM-1 (counter receptor of the VLA-4 integrin) binding assay on BM CD34+ cells. Our results demonstrated that CD34+CD9+ cells preferentially bound to soluble VCAM-1 (17.2%-51.4% VCAM-1-bound cells in CD9+ cells vs 12.8%-25.9% in CD9- cells; n = 10, P ≤ .0003), suggesting that CD9+ cells possess higher VLA-4 activity. Concomitant with decreased CD9 expression, MPB CD34+ cells exhibited lower VCAM-1 binding ability (2.8%-4.0% VCAM-1-bound cells; n = 3), when compared to BM CD34+ cells (15.5%-37.7%; n = 10, P < .0130). In vivo treatment of NOD/SCID chimeric mice with G-CSF reduced VCAM-1 binding of CD34+ cells in the BM by 49.0% (n = 5, P = .0010). Importantly, overexpression of CD9 in CB CD34+ cells promoted VCAM-1 binding by 39.5% (n = 3, P = .0391), thus providing evidence that CD9 regulates VLA-4 activity. Preliminary results also indicated that enforcing CD9 expression in CB CD34+ cells could enhance their homing and engraftment in the NOD/SCID mouse model. Our findings collectively established that CD9 expression and associated integrin VLA-4 activity are dynamically regulated in the BM microenvironment, which may represent important events in governing stem cell engraftment and mobilization. Strategies to modify CD9 expression could be developed to enhance engraftment or mobilization of CD34+ cells. Disclosures No relevant conflicts of interest to declare.

scholarly journals Inhibition of Lysine-Specific Demethylase 1A (LSD1) Supports Human HSCs in Culture By Preserving Their Immature State

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 194-194
Author(s):  
Agatheeswaran Subramaniam ◽  
Mehrnaz Safaee Talkhoncheh ◽  
Kristijonas Zemaitis ◽  
Shubhranshu Debnath ◽  
Jun Chen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bone Marrow ◽  
Stem Cell ◽  
Cell Division ◽  
Molecular Mechanisms ◽  
Conflicts Of Interest ◽  
Enrichment Score ◽  
Hematopoietic Stem ◽  
Cd34 Cells ◽  
Human Hscs

Abstract The molecular mechanisms that govern hematopoietic stem cell (HSC) fate decisions remain incompletely defined. It has been a long-standing goal in the field to gain a better understanding of the genes and pathways that regulate the self-renewal ability of HSCs in order to develop optimal culture conditions in which HSCs can be expanded for clinical benefit. Lysine-specific histone demethylase 1A (LSD1), also known as lysine (K)-specific demethylase 1A (KDM1A), regulates gene expression by specifically eliminating di- and mono-methyl groups on H3 lysine K4 and K9 residues. Studies in mice have shown that, conditional knockdown of LSD1 results in an expansion of bone marrow hematopoietic stem and progenitor cells (HSPCs). However, a complete knockout of LSD1 results in pancytopenia and a dramatic reduction of HSPCs. In this study, we asked whether inhibition of LSD1 would improve the maintenance or expansion of cultured human HSCs derived from umbilical cord blood (UCB). To evaluate the effect of LSD1 inhibition we treated UCB CD34+ cells with three different LSD1 inhibitors (2-PCPA, GSK-LSD1 and RN1) at their respective IC50 values (20µM, 16nM and 70nM) and expanded the cultures for 6 days in serum free medium supplemented with stem cell factor (SCF), thrombopoietin (TPO) and FMS-like tyrosine kinase 3 ligand (FLT3L). Since we (Subramaniam et. al. Haematologica 2018) and others recently have shown that EPCR is a reliable cell surface marker to track UCB derived HSCs during in vitro culture, we quantified the numbers of CD34+EPCR+ cells using flow cytometry and compared to DMSO treated control cultures. Remarkably, treatment with either 2-PCPA or GSK-LSD1 resulted in a more than 10-fold increase of CD34+EPCR+ cells, compared to controls. Further, from dose response experiments we found that 2-PCPA at 1.25 µM expanded the total CD34+ cell population more efficiently than GSK-LSD1, and we therefore used 2-PCPA at this concentration for the subsequent experiments. Using carboxyfluorescein succinimidyl ester (CFSE) labeling to monitor cell division, we found that 2-PCPA did not significantly alter the cell division rate of the cultured CD34+ cells compared to DMSO controls, suggesting that the expansion of CD34+EPCR+ cells is not due to increased proliferation, and that LSD1 inhibition rather may prevent differentiation of the immature HSPCs. To further explore this, we mapped the early transcriptional changes triggered by 2-PCPA in HSCs using gene expression profiling of CD34+CD38-CD45RA-CD90+ cells following 24 hours of culture with or without 2-PCPA treatment. We found that gene sets corresponding to UCB and fetal liver HSCs were significantly enriched upon 2-PCPA treatment compared to DMSO control (Normalized Enrichment Score (NES)=1.49, q=0.05). This suggest that 2-PCPA indeed restricts differentiation and preserves the HSC state upon ex vivo culture. Strikingly, the gene signature induced by LSD1 inhibition was highly similar to that induced by the known HSC expanding compound UM171 (NES=1.43, q=0.11). UM171 is a molecule with unknown target and has also been shown to dramatically expand the EPCR+ population in culture. Finally, the frequency of functional HSCs in DMSO and 2-PCPA treated cultures were measured using limiting dilution analysis (LDA). LDA was performed by transplanting 4 doses (day 0 equivalents of 20000, 1000, 300 and 100 CD34+ cells) of DMSO and 2-PCPA treated cultures into sub lethally irradiated (300cGy) NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) mice. Human CD45+ cell engraftment in the bone marrow was analyzed 18 weeks' post transplantation. Cultures treated with 2-PCPA showed a 5-fold higher content of long-term repopulating cells per day 0 CD34+ cell equivalent compared to the DMSO control (1 in 615 vs 1 in 3041, p=0.03). Thus, the 2-PCPA treated cultures had significantly enhanced HSCs numbers. To determine the absolute expansion rate, we are currently performing LDA using uncultured cells as well. Altogether our data suggest that LSD1 inhibition supports both phenotypic and functional HSCs in culture by preserving the immature state. Currently we are exploring the possibilities of using LSD1 inhibitors in combination with other known modifiers of HSC expansion. Disclosures No relevant conflicts of interest to declare.

scholarly journals Trends in TRECs values according to age and gender in Chinese children, and their clinical application

2021 ◽  
Author(s):  
Qin Zhao ◽  
Xiao-Dong Zhao
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Receptor ◽  
Cell Receptor ◽  
Chinese Children ◽  
Hematopoietic Stem ◽  
Naive T Cells ◽  
Cell Numbers ◽  
Naïve T Cells ◽  
And Gender

T cell receptor excision circles (TRECs) are small circularized DNA elements produced during rearrangement of T cell receptor (TCR) genes. Because TRECS are fairly stable, do not replicate during mitosis, and are not diluted during division of naïve T cells1, they are suitable for assessing the number of newly formed T cells 2. In this study, we detected TRECs in 475 healthy Chinese children aged 0–18 years in different clinical settings. We found a strong correlation between TRECs levels and peripheral CD4 naïve T cell numbers, but not between TRECs levels and effector or memory CD4 and CD8 T cell numbers. TRECs levels fell significantly compared with normal controls in patients with severe combined immunodeficiencies (SCID) (n=7), wiskott-aldrich syndrome (WAS) (n=22), or activated PI3Kδ syndrome (APDS) (n=5). TRECs levels in those with signal transducer and activator of transcription 1 (STAT1) deficiency (n=8) decreased or did not change significantly, a finding consistent with that for CD4 naïve T cells. We also measured TRECs levels in seven PIDs after hematopoietic stem cell transplantation (HSCT) (WAS=5; chronic granulomatous disease (CGD)=2), and found the complications after HSCT may reduce TRECs levels by interfering with production of naïve T cells. In conclusion, we established reference values for TRECs, which can be used to screen for primary immunodeficiency diseases (PIDs) during early life and track immune reconstitution after HSCT.

scholarly journals Human allogeneic stem cell maintenance and differentiation in a long- term multilineage SCID-hu graft

Blood ◽  
1995 ◽  
Vol 86 (5) ◽  
pp. 1680-1693 ◽  
Author(s):  
CC Fraser ◽  
H Kaneshima ◽  
G Hansteen ◽  
M Kilpatrick ◽  
R Hoffman ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
B Cells ◽  
Myeloid Cells ◽  
Cell Populations ◽  
Multilineage Differentiation ◽  
Hematopoietic Stem ◽  
Cd34 Cells ◽  
Stem Cell Populations

The ability to determine the functional capacity of putative human hematopoietic stem cell (HSC) populations requires in vivo assays in which long-term multilineage differentiation can be assessed. We hypothesized that if human fetal bone was transplanted adjacent to a fetal thymus fragment in severe combined immunodeficient (SCID) mice, a conjoint organ might form in which HSC in the human bone marrow (BM) would mimic human multilineage differentiation into progenitor cells, B cells, and myeloid cells; undergo self-renewal; and migrate to and differentiate into T cells within the thymic microenvironment. To test this possibility, SCID mice were transplanted subcutaneously with HLA class I mismatched fetal bone, thymus, and spleen fragments (SCID-hu BTS). We found that the BM of SCID-hu BTS grafts maintained B cells, myeloid cells, CD34+ cells for at least 36 weeks posttransplant. Assayable hematopoietic progenitors colony-forming units-granulocyte- macrophage were present in 100% (66/66) of grafts over a period of 28 weeks. Cells with a HSC phenotype (CD34+Thy-1+Lin-) were maintained for 20 weeks in SCID-hu BTS grafts. These CD34+Thy-1+Lin- cells had potent secondary multilineage reconstituting potential when isolated and injected into a secondary HLA mismatched SCID-hu bone assay and analyzed 8 weeks later. In addition, early progenitors within the BM of SCID-hu BTS grafts were capable of migrating to the human thymus and undergoing differentiation through immature CD4+CD8+ double-positive T cells and produce mature T cells with a CD4+CD8- or CD8+CD4- phenotype that could be detected for at least 36 weeks. Phenotypically defined human fetal liver (FL) and umbilical cord blood (UCB) hematopoietic stem cell populations were injected into irradiated SCID-hu BTS grafts to assess their multilineage repopulating capacity and to assess the ability of the BTS system to provide an environment where multiple lineages might differentiate from a common stem cell pool. Injection of irradiated grafts with FL HSC or UCB HSC cells resulted in donor- derived B cells, myeloid cells, immature and mature T cells, and CD34+ cells in individual grafts when analyzed 8 weeks postreconstitution, further showing the multipotential nature of these stem cell populations. In addition, a strong correlation was observed between maintenance of host graft-derived CD8+ cells and failure of donor stem cell engraftment.(ABSTRACT TRUNCATED AT 400 WORDS)

Runx1-Cbfb Interacts with CHD7, a Chromatin Modifying Enzyme with a Potential Role in Hematopoiesis

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1300-1300
Author(s):  
Jingmei Hsu ◽  
Chung-Tsai Lee ◽  
Scott Gerber ◽  
Shuqian Yu ◽  
Nancy A. Speck
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Hematopoietic Stem Cell ◽  
Conflicts Of Interest ◽  
Myeloproliferative Neoplasms ◽  
Heart Defects ◽  
Genetic Alterations ◽  
Transactivation Domain ◽  
Hematopoietic Stem

Abstract Abstract 1300 Mutations in RUNX1 and CBFB are among the most common genetic alterations in hematologic malignancies, including acute myeloid and lymphoid leukemia (AML, ALL), chronic myelomonocytic leukemia (CMML), myelodysplastic syndrome and myeloproliferative neoplasms. Loss of Runx1-CBFb causes a failure of hematopoietic stem cell emergence during embryogenesis. Critical roles for Runx1-CBFb in adult hematopoiesis include hematopoietic stem and progenitor homeostasis, and lymphoid and megakaryocytic differentiation. We took an unbiased co-immunoprecipitation and mass spectrometry approach to identify Runx1-CBFb co-regulators in T cells, and identified chromodomain helicase binding protein 7 (CHD7) as a potential interacting partner. CHD7 is an ATP-dependent chromatin remodeling protein that primarily occupies enhancer and promoter regions. Autosomal dominant mutations in CHD7 cause CHARGE syndrome (Coloboma of the eye, Heart defects, Atresia of the choanae, Retardation of growth and/or development, Genital and/or urinary abnormalities, and Ear abnormalities and deafness). It was shown that CHD7 interacts with Sox2, and its occupancy correlates with H3K4me1/2 modifications and P300 binding at enhancer regions, and H3K4me3 marks at promoters. We confirmed the interaction of endogenous Runx1 and CHD7 in T cells. We demonstrate that the Runx1 transactivation domain, which is critical at all stages of hematopoiesis, is required for the CHD7 interaction. To elucidate an in vivo function for CHD7 in hematopoiesis, we generated a conditional pan-hematopoietic Chd7 deletion in mice using a floxed Chd7 allele and Vav1-Cre. Deletion of Chd7 in hematopoietic cells appears to cause no lineage specific defects. However, CHD7 deficient bone marrow cells had a competitive advantage in T cell reconstitution as compared to wild type cells, suggesting a role for CHD7 in restraining T cell numbers in the adult. Determining how CHD7 exerts its functions should shed light on underlying mechanisms in hematopoietic stem cell formation, T cell development, and hematopoietic malignancies. Disclosures: No relevant conflicts of interest to declare.

Sign in / Sign up

Export Citation Format

Share Document